Detect Network collisions? 1

[klabaza]

Hi i have some problems between 2 LANS, they are connected with one poit to point link

LAN1--Router---PtP---Router--LAN2

The problem is that we have some big rate collisions 36% packets loss went i test with ping on bussines hours is to much.

Is a switch network, i want to know wich software i can use to find who is making this problem, before the switches was working at 100mb Half Duplex, but i change to 100Mb Full Duplex, now the problem is between my 2 LANS, maybe the problem is my ISP, but i need to first check that my problem is local, them wich software i can use and where to put the device to monitor the traffic, a hub between my router and my lan or where...?

I can use freebsd/linux/windows monitor the network.

Any advice or links i will apreciated, thanks all for your help.

 

[PalmTest]

You changed the switch from 100HD to 100FD.
Did you also change the duplex mode on the switchport where your router is attached to?
Is the speed and duplex mode on the Ethernet side of your Router also changed?
When the switchport is 100FD and the Ethernet side of the router is 100HD then collisions appear.

 

[jimbopalmer]

I wrote a FAQ on duplex, it may explain slower than expected throughput.

http://tek-tips.com/faqs.cfm?fid=4186

In a full duplex switched network, collisions do not happen, the closest is that the switches port buffers can overflow, some vendors switches report this as a collision.

What vendor/model switches? If they are managed, there may be good error reporting.

I tried to remain child-like, all I acheived was childish.

 

[klabaza]

Hi.

My switches are baystack 350 24 ports, and the 2 routers are NetPerformer SDM-9360.

The switch say that the router port is working at 100FD, but i want to confirm at which speed the router is working??? I access the router and didnt find anything about the speed, on the back the led indicated 100Mb but FD or HD?

I need to ask how to check the speed of the router. I have the manual i hope to find the answer there, i will stay in tuch, thanks to all.

 

[klabaza]

Hi people.

One big mistake of my part, after analize the problem, i confused collisions with dropped packets.

My problem is that one of the routers are dropping packets, i was reading about and normally went one device is dropping packets is because it cannot handle the transfer rate, this is correct?

If this is the reason, how to count the transfer rate...? SNMP? or what else to do?

Thanks.

 

[PalmTest]

Dropping packets can be because the network is overcrowded.
It might even be because the router and the switch are not compatible.
(I had one issue where the specs of the switch did not match the IEEE specs and the router matched IEEE precisely. This caused an electrical incompatibility between the two, which was very hard to find out.)

If you set the switchport, where the router connects to, to 100HalfDuplex do the dropped packets still occur ?
Is it possible to increase the receive buffer in the router ?
Is it possible to connect the router to a different switch, or different switchport?

HTH.